COVID-19 vaccination during or just prior to pregnancy and hypertensive disorders of pregnancy

Q: What are the key findings of this study?

COVID-19 vaccination during or just prior to pregnancy was associated with a higher risk of self-reported hypertensive disorders of pregnancy compared to unvaccinated women (aRR 1.24, 95% CI 1.08-1.43).

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Hypertensive disorders of pregnancy (HDP) (n=16048). Intervention: COVID-19 vaccination during pregnancy or within 30 days prior to last menstrual period vs. Unvaccinated pregnant women (PRAMS cohort). Primary outcome: Self-reported hypertensive disorders of pregnancy (high blood pressure starting during pregnancy or pre-eclampsia) (aRR 1.24, 95% CI 1.08, 1.43, p=<0.0001).

Q: What question did this study set out to answer?

To assess whether COVID-19 vaccination during pregnancy or within 30 days before the last menstrual period, or COVID-19 illness in pregnancy, is associated with hypertensive disorders of pregnancy.

Andrea J. Sharma; Ashley Smoots; Sabrina A. Madni; Lauren Head Zauche; Ansley Waters; Aliza Machefsky; David K. Shay; Cameron Hinrichsen; Jenna Chambless; Kendra M. Norris; Sarah Thompson; Deanna Cole; Chris Ibegbu; Christine K. Olson

doi:10.1016/j.vaccine.2026.128268

February 2, 2026VaccineOpen Access

COVID-19 vaccination during or just prior to pregnancy and hypertensive disorders of pregnancy

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Key result

Periconceptional COVID-19 vaccination linked to ~24% higher risk of hypertensive disorders of pregnancy.

aRR 1.24
95% CI 1.08, 1.43
P<0.0001
n=16,048

Key Points

To assess whether COVID-19 vaccination during pregnancy or within 30 days before the last menstrual period, or COVID-19 illness in pregnancy, is associated with hypertensive disorders of pregnancy.
Matched cohort study linking vaccinated nulliparous women from the CDC's COVID-19 Vaccine Pregnancy Registry (C19VPR, December 2020–March 2022) to unvaccinated women from the Pregnancy Risk Assessment Monitoring System (PRAMS, 2019–2021).
Eligible participants with singleton live births were matched 1:1 (8024 matched pairs) on maternal age group, race and ethnicity, and gestational age at delivery.
Relative risk (RR) for self-reported hypertensive disorders of pregnancy (HDP) was estimated using Poisson regression adjusted for confounders, with interaction testing for vaccine manufacturer and gestational timing.
Self-reported HDP occurred in 15.0% of C19VPR participants compared to 12.0% of PRAMS participants, with an adjusted RR of 1.24 (95% CI: 1.08, 1.43).
No effect modification was observed by vaccine manufacturer (p-value for interaction = 0.94) or vaccination timing before versus at or after 20 weeks' gestation (p-value for interaction = 0.66).
Among matched pairs with COVID-19 illness data (n = 4039), participants reporting illness during pregnancy had an adjusted RR for HDP of 1.28 (95% CI: 1.02, 1.60) compared to those reporting no illness.

Study Design

Type

Cohort (n=16,048)

Multicenter

Yes

PICO

P

Population

16,048 nulliparous pregnant women (8,024 matched pairs) aged 18-54 years with singleton live births and no prior chronic hypertension across the United States.

E

Exposure / Comparator

COVID-19 vaccination during pregnancy or within 30 days prior to last menstrual period vs Unvaccinated pregnant women (PRAMS cohort)

O

Primary Outcome

Self-reported hypertensive disorders of pregnancy (high blood pressure starting during pregnancy or pre-eclampsia) — aRR 1.24 (1.08, 1.43), p=<0.0001

Main Result

Relative Risk: 1.24 (95% CI 1.08–1.43)

Absolute Event Rate: 15% vs 12%

p-value: p=<0.0001

Limitations

Self-reported data subject to misclassification and reporting bias
Vaccinated and unvaccinated groups were sampled from two different cohorts (C19VPR vs PRAMS) with different recruitment and data collection methods
High proportion of healthcare workers in the vaccinated cohort introducing unmeasured differences in stress, education, and health-seeking behavior
Temporal differences in delivery dates (unvaccinated participants delivered on average 11.4 months earlier, often prior to the pandemic)
Inability to differentiate HDP diagnostic subcategories by severity
Unmeasured confounding from factors not collected in both datasets (e.g., smoking, alcohol, assisted reproductive technologies, gestational weight gain, urban residence)

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Answers are grounded in this paper and cite their sources.

Implication

Matched cohort study evaluates hypertensive disorder risks during pregnancy related to COVID-19 vaccination and illness.

Abstract

Hypertensive disorders of pregnancy (HDP) are leading causes of maternal and fetal morbidity/mortality. To identify potential safety concerns, we evaluated whether COVID-19 vaccination during pregnancy or within 30 days of last menstrual period was associated with self-reported HDP. We also evaluated HDP risk associated with COVID-19 illness during pregnancy. We conducted a matched cohort study using data from the Centers for Disease Control and Prevention's COVID-19 Vaccine Pregnancy Registry (C19VPR; vaccinated) and Pregnancy Risk Assessment Monitoring System (PRAMS; unvaccinated). Participants included nulliparous women with singleton pregnancies ending in livebirth (C19VPR, December 2020-March 2022; PRAMS, 2019-2021). Participants were matched by age group, race/ethnicity, and gestational age at delivery. We estimated relative risk (RR) for self-reported HDP by vaccination status using Poisson regression, adjusting for confounders. We tested for effect modification by vaccine manufacturer and vaccination timing (<20 or ≥ 20 weeks' gestation). Among matched pairs with data on self-reported COVID-19 illness in pregnancy, we estimated risk of HDP by illness status. Of 8030 eligible C19VPR participants, 8024 (99.9%) were matched to a PRAMS participant. Most C19VPR participants delivered in 2021 (98.9%); PRAMS participants delivered predominantly in 2020 (54.5%) and 2019 (17.4%). Adjusted RR for HDP was 1.24 (95% confidence interval [CI]: 1.08, 1.43) among C19VPR versus PRAMS participants. We observed no effect modification. Results of an analysis restricted to matched pairs who delivered in 2021 (n = 2231) were similar. Among matched pairs (n = 4039) with data on COVID-19 illness in pregnancy, adjusted RR for HDP was 1.28 (95%CI: 1.02, 1.60) for those reporting illness compared with no illness. Risk of HDP was higher among COVID-19 vaccinated compared to unvaccinated women; however, the two groups were sampled from different cohorts. Risk was similar to those who reported COVID-19 illness. Given cohort differences, the associations observed cannot be considered causal; updated assessments of HDP risks after illness and vaccination would be useful.

Discussion

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Cite This Study

Sharma et al. (2026) conducted a cohort in Hypertensive disorders of pregnancy (HDP) (n=16,048). COVID-19 vaccination during pregnancy or within 30 days prior to last menstrual period vs. Unvaccinated pregnant women (PRAMS cohort) was evaluated on Self-reported hypertensive disorders of pregnancy (high blood pressure starting during pregnancy or pre-eclampsia) (aRR 1.24, 95% CI 1.08, 1.43, p=<0.0001). COVID-19 vaccination during or just prior to pregnancy was associated with a higher risk of self-reported hypertensive disorders of pregnancy compared to unvaccinated women (aRR 1.24, 95% CI 1.08-1.43).

synapsesocial.com/papers/698584b78f7c464f230081cf https://doi.org/10.1016/j.vaccine.2026.128268

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COVID-19 vaccination during or just prior to pregnancy and hypertensive disorders of pregnancy

Key Points

Study Design

PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

COVID-19 vaccination during or just prior to pregnancy and hypertensive disorders of pregnancy

Key Points

Study Design

PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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